A behavioral and eye movement study on inhibitory processing of action memory.

Recent evidence highlights the critical role of effective interference inhibition for optimal memory performance, yet its function in action memory remains relatively underexplored. The current study investigated inhibitory processes in action memory during encoding and storage stages. In Experiment 1, 100 participants were divided into high and low cognitive inhibition groups using the Stroop color naming task. They performed either a subject-performed task (SPT) or a verbal task (VT) under varying semantic interference levels to assess the interaction between individual inhibitory abilities and the inhibition processing of action memory during encoding. Results indicated no significant difference in inhibition effects (IF) between high and low inhibition groups in SPT under high semantic interference, while in VT, those with high cognitive inhibition demonstrated significantly greater IF than those with low. Experiment 2, involving 57 participants, employed a point detection task and eye-tracking to explore attentional inhibition mechanisms during action memory storage. Behavioral results showed greater IF for SPT than VT under semantic interference. Eye-tracking revealed higher initial fixation rates and shorter durations for SPT subjects during the early processing stage, and significantly fewer and shorter fixations in the later stage compared to VT subjects. These findings imply stronger inhibitory processing in SPT during both encoding and storage stages under semantic interference, with attentional inhibition of action memories occurring predominantly in the later stage.

General deficits of attentional inhibition in high trait anxiety: ERP evidence.

Behavioral evidence shows that individuals with high trait anxiety tend to be distracted by irrelevant stimulation not only for threat-related stimuli but also for non-emotional neutral stimuli. These findings suggest that there may be a general deficit of attentional control in trait anxiety. However, the neural mechanism underlying the anxiety-related deficit in attentional control, especially inhibition function, is still unclear. Here, we examined the attentional processing of the non-emotional neutral distractor on 66 young adults with different levels of trait anxiety, using the ERP indices of attentional selection (N2pc) and top-down inhibition (Pd) in a search task with geometric stimuli. We found that the distractor-evoked N2pc amplitude did not vary with anxiety levels, but increased anxiety was associated with smaller Pds (i.e. worse inhibition). Besides, delayed attentional selection of targets was associated with higher anxiety levels. These correlations of trait anxiety remained significant even after controlling for state anxiety, and state anxiety did not affect the attentional processing of distractors and targets, suggesting that trait anxiety, not current anxiety, affects attentional function. Our findings clarify the mechanism underlying the general attentional deficits in trait anxiety, e.g. reduced distractor inhibition and delayed target selection.

Nicotine promotes the utility of short-term memory during visual search in macaque monkeys.

RATIONALE: The central cholinergic system is a major therapeutic target for restoring cognitive functions. Although manipulation of cholinergic signaling is known to alter working memory (WM), the underlying mechanism remains unclear. It is widely accepted that WM consists of multiple functional modules, one storing short-term memory and the other manipulating and utilizing it. A recently developed visual search task and a relevant model can be used to assess multiple components of WM during administration of acetylcholine receptor (AChR)-related substances. OBJECTIVES: The effects of systemic administration of AChR-related agents on WM and eye movements were examined during the oculomotor foraging task. METHODS: Three monkeys performing the task received an intramuscular injection of saline or the following AChR-related agents: nicotine (24 or 56 µg/kg), mecamylamine (nicotinic AChR antagonist, 1.0 mg/kg), oxotremorine (muscarinic AChR agonist, 3.0 µg/kg), and scopolamine (muscarinic AChR antagonist, 20 µg/kg). The task was to find a target among 15 identical objects by making eye movements within 6 s. The data were analyzed according to the foraging model that incorporated three parameters. RESULTS: Nicotine and mecamylamine significantly increased the utility but not the capacity of short-term memory, while muscarinic AChR-related agents did not alter any WM parameters. Further regression analyses with a mixed-effect model showed that the beneficial effect of nicotine on memory utility remained after considering eye movement variability, but the beneficial effect of mecamylamine disappeared. CONCLUSIONS: Nicotine improves visual search, mainly by increasing the utility of short-term memory, with minimal changes in oculomotor parameters.

Inhibitory attentional control under cognitive load in social anxiety: An investigation using a novel dual-task paradigm.

Research suggests that socially anxious (SA) individuals exhibit poorer attentional inhibition than their non-anxious (NA) counterparts. Attentional control theory presumes that cognitive load worsens the adverse effects of anxiety on attentional inhibition. However, previous studies examined the effects of cognitive load on attentional inhibition in social anxiety yielded inconsistent results. In this study, cognitive load was manipulated by adding a 1-back (low cognitive load) and 2-back task (high cognitive load) to the emotional antisaccade task, investigating the effects of cognitive load on attentional inhibition in the presence of social evaluative stimuli in SA and NA individuals. Results revealed that cognitive load improved the efficiency but impeded the effectiveness of inhibitory attentional control in SA participants. Under high cognitive load, SA participants made more erroneous saccades for threat-related than nonthreat-related faces while NA participants showed no differences in error rates among different face types. Moreover, regardless of cognitive levels, SA participants had shorter saccade latencies for angry faces than happy and neutral faces. NA participants did not show differences in saccade latencies among different face types. Implications of these findings for understanding the role that cognitive load plays in the processes of attentional control and interventions for social anxiety are discussed.

Decline in attentional inhibition among migraine patients: an event-related potential study using the Stroop task.

BACKGROUND: As a disorder of brain dysfunction, migraine has been associated with cognitive decline. However, no consistent results with respect to the attention function in migraineurs have been found, and the relationship between attentional inhibition and migraine is also unclear. In this study, the attentional inhibition function was evaluated using event-related potentials (ERPs) while migraine patients and healthy controls were performing the color-word Stroop task. METHODS: In this study, 75 migraine patients and 41 age-, gender-, and education-matched healthy controls were enrolled. The Stroop task was performed, and both behavioral and ERP data were analyzed. RESULTS: As to the behavioral data, the migraine group had a longer reaction time compared to the control group, but no difference in Stroop effect was observed. With respect to ERP components, the amplitudes of both early and late medial frontal negativity (MFN) were decreased in the migraine group. Additionally, obvious differences in the early MFN and sustained potential (SP) amplitudes were found between patients with and without allodynia. CONCLUSIONS: At the behavioral level, migraine patients exhibited decreased executive ability but no obvious decline in inhibition. By contrast, a decline in attentional inhibition during the migraine interictal phase was confirmed by the analysis of ERP components, mainly those associated with changes in the conflict-monitoring stage, independent of confounding factors such as age, education, medication and mood disorders. Migraine patients with allodynia exhibited some significant differences in early MFN and SP compared to those without, supporting the hypothesis that migraine chronification aggravates the decline in attentional inhibition.

In support of selective rehearsal: Double-item presentation in item-method directed forgetting.

Despite the substantial evidence highlighting the role of selective rehearsal in item-method directed forgetting, recent work has suggested that forgetting may occur as a function of an active inhibitory mechanism that is more effortful than elaborative rehearsal processes. In the present work, we test this hypothesis by implementing a double-item presentation within the item-method directed forgetting paradigm. Participants studied two unrelated items at a time. Some words were followed by the same cue, and participants were instructed to remember or forget both items (pure condition). On other trials, participants were to remember one but forget the other word (mixed condition). Selective rehearsal and inhibition accounts make distinct predictions regarding memory performance in the double-item presentation. In Experiment 1, we compared recognition performance in the pure and mixed conditions, while in Experiment 2, we included a neutral baseline condition to further distinguish between the selective rehearsal and inhibition accounts. Contrary to the inhibition account but consistent with selective rehearsal, we found for both remember and forget items that recognition was greater in the mixed than in the pure condition. Recognition for forget items also did not differ from neutral items. We conclude that selective rehearsal, not inhibition, is responsible for item-method directed forgetting.

An EZ-Diffusion Model Analysis of Attentional Ability in Patients With Retinal Pigmentosa.

Retinitis pigmentosa (RP) is characterized by visual acuity decrease and visual field loss. However, the impact of visual field loss on the cognitive performance of RP patients remains unknown. In the present study, in order to understand whether and how RP affects spatial processing and attentional function, one spatial processing task and three attentional tasks were conducted on RP patients and healthy controls. In addition, an EZ-diffusion model was performed for further data analysis with four parameters, mean decision time, non-decision time, drift rate, and boundary separation. It was found that in the spatial processing task, compared with the control group, the RP group exhibited a slower response speed in large and medium visual eccentricities, and slower drift rate for the large stimulus, which is strongly verified by the significant linear correlation between the visual field eccentricity with both reaction time (p = 0.047) and non-decision time (p = 0.043) in RP patients. In the attentional orienting task and the attentional switching task, RP exerted a reduction of speed and an increase of non-decision time on every condition, with a decrease of drift rate in the orienting task and boundary separation in the switching task. In addition, the switching cost for large stimulus was observed in the control group but not in the RP group. The stop-signal task demonstrated similar inhibition function between the two groups. These findings implied that RP exerted the impairment of spatial cognition correlated with the visual field eccentricity, mainly in the peripheral visual field. Moreover, specific to the peripheral visual field, RP patients had deficits in the attentional orienting and flexibility but not in the attentional inhibition.

Differential inter-trial effects in the visual search of children, adolescents, and young adults.

We examined the age-related variation in one type of inter-trial effect of visual search, the distractor previewing effect (DPE), in affectively neutral and affectively charged contexts. In Experiment 1, children, adolescents, and young adults were faster to identify the shape of a color target when the color of the current distractors had already been previewed than when the target had been previewed in the preceding target-absent trial, indicative of a color-based DPE. The results revealed a greater DPE in children than in adolescents and young adults, but it can be attributed to children's slower RTs than the other two groups. In Experiment 2, children, adolescents, and young adults were instructed to respond to a schematic face that was different from the other two faces. Young adults were faster in searching for a threatening face among friendly ones when they had previewed a target-absent display consisting of friendly faces than that of threatening faces, indicating an emotional DPE. By contrast, children showed a reversed DPE under the same condition, whereas adolescents showed no DPE. Taken together, these results suggested that the three age groups were all able to create an inhibitory attentional bias on the basis of trial history in affectively neutral context, whereas children and adolescents were not able to create such an inhibitory attentional bias in affectively charged contexts in the same way as adults did. These findings implied that the development of attentional inhibition abilities in affectively charged contexts might be delayed compared to those in affectively neutral contexts.

A Hierarchical Model of Inhibitory Control.

Inhibitory control describes the suppression of goal-irrelevant stimuli and behavioral responses. Current developmental taxonomies distinguish between Response Inhibition - the ability to suppress a prepotent motor response, and Attentional Inhibition - the ability to resist interference from distracting stimuli. Response Inhibition and Attentional Inhibition have exhibited moderately strong positive correlations in previous studies, suggesting they are closely related cognitive abilities. These results may reflect the use of cognitive tasks combining Stimulus-Stimulus- and Stimulus-Response-conflict as indicators of both constructs, which may have conflated their empirical association. Additionally, previous statistical modeling studies have not controlled for individual differences in Working Memory Capacity, which may account for some of the empirical overlap between Response Inhibition and Attentional Inhibition. The aim of the current study was to test a hierarchical model of inhibitory control that specifies Working Memory Capacity as a higher-order cognitive construct. Response Inhibition and Attentional Inhibition were conceptualized as lower-order cognitive mechanisms that should be empirically independent constructs apart from their shared reliance on Working Memory Capacity for active maintenance of goal-relevant representations. Measures of performance on modified stimulus-response compatibility tasks, complex memory span, and non-selective stopping tasks were obtained from 136 preadolescent children (M = 11 years, 10 months, SD = 8 months). Consistent with hypotheses, results from Structural Equation Modeling demonstrated that the Response Inhibition and Attentional Inhibition factors were empirically independent constructs that exhibited partial statistical dependence on the Working Memory Capacity factor. These findings have important implications for current theories and models of inhibitory control during development.

Neural evidence that inhibition is linked to the affective devaluation of distractors that match the contents of working memory.

Stimuli appearing as visual distractors subsequently receive more negative affective evaluations than novel items or prior targets of attention. Leading accounts question whether this distractor devaluation effect occurs through evaluative codes that become associated with distractors as a mere artefact of attention-task instructions, or through affective consequences of attentional inhibition when applied to prevent distractor interference. Here we test opposing predictions arising from the evaluative-coding and devaluation-by-inhibition hypotheses using an electrophysiological marker of attentional inhibition in a task that requires participants to avoid interference from abstract-shape distractors presented while maintaining a uniquely-colored stimulus in memory. Consistent with prior research, distractors that matched the colour of the stimulus being held in memory elicited a Pd component of the event-related potential waveform, indicating that their processing was being actively suppressed. Subsequent affective evaluations revealed that memory-matching distractors also received more negative ratings than non-matching distractors or previously-unseen shapes. Moreover, Pd magnitude was greater on trials in which the memory-matching distractors were later rated negatively than on trials preceding positive ratings. These results support the devaluation-by-inhibition hypothesis and strongly suggest that fluctuations in stimulus inhibition are closely associated with subsequent affective evaluations. In contrast, none of the evaluative-coding based predictions were confirmed.

The mental-attention Tai Chi effect with older adults.

BACKGROUND: Tai Chi practice has some fitness, wellness, and general cognitive effects in older adults. However, benefits of Tai Chi on specific mental-attentional executive processes have not been investigated previously. We studied older Canadian adults of Chinese and non-Chinese origin and from low socioeconomic areas. METHODS: Sixty-four adults (51-87 years old) took part in a 16-week Tai Chi program. There were two groups: Chinese-background (n = 35) and Non-Chinese-background (n = 29). They received four mental-attention executive tasks before and after the 16-week period. These tasks measured visuospatial reasoning, mental-attentional activation (working memory), attentional inhibition, and balance between these attention factors (field-dependence-independence). RESULTS: Chinese participants showed significant gain on Figural Intersections Task (mental-attentional capacity), Antisaccade (attentional inhibition), and Matrix Reasoning (fluid intelligence measure). Both groups evidenced gain on the Water Level Task (attentional balance). CONCLUSIONS: These gains suggest that Tai Chi can improve mental-attentional vigilance and executive control, when practitioners are sufficiently motivated to pursue this practice, and apply themselves (as our Chinese participants seem to have done). We found that Tai Chi enhanced mental attentional executives in the Chinese sample. The largely negative results with Non-Chinese participants might be explained by less strong motivation and by the relatively short Tai Chi practice period, which contrasts with the prior familiarity with Tai Chi of the Chinese participants.

An attentional inhibitory deficit for irrelevant information in obsessive-compulsive disorder: evidence from ERPs.

Previous studies on attentional bias have demonstrated that patients with obsessive-compulsive disorder (OCD) have an overall longer reaction time (RT) for various stimuli. It was hypothesized that this general slowness may indicate the presence of an attentional inhibition deficit in OCD. To test the hypothesis, event-related potentials (ERPs) were recorded in 31 non-medicated OCD patients and 29 age-, handedness- and sex-matched healthy controls while they performed an emotional Stroop task (EST). Relative to the control subjects, the OCD patients had similar interference effects for negative words, but an overall longer RT and larger P2 and P3 amplitudes to all words. These results support the notion that OCD is characterized by an attentional inhibitory dysfunction for irrelevant information.